1. Field of the Invention
This invention relates to an auxiliary adjusting mechanism for optical instruments, such as microscopes, and particularly to an adjusting mechanism which cooperates with the normal coarse/fine adjusting shaft and may be used as an alternative thereto for providing relative movement of one member with respect to another, such as a stage relative to the viewing optics.
2. Description of the Prior Art
In the past, precision optical instruments, such as miroscopes, have commonly used coarse and fine adjusting shafts for providing movement of one member relative to another. The coarse and fine adjusting shafts may be separate from each other, or as is more common in precision instruments, the shafts may be mounted coaxially to each other. In either event, the adjusting shafts are coupled to an adjustable member, such as a stage or head assembly, by any convenient manner so that rotation of the shaft(s) produces a corresponding and proportional amount of movement in the movable manner.
Depending on the type of instrument being utilized, many of the coarse/fine adjusting mechanisms used in the past were awkward to reach for some operators and therefore difficult to manipulate. An additional shortcoming is that in many instances neither the coarse nor the fine adjustments provide the appropriate adjustments.
There have been numerous attempts to address the problem of providing an alternative to the adjustments provided by the normal coarse and fine mechanisms. U.S. Pat. No. 4,083,256 issued Apr. 11, 1978 to M. Shio is typical and discloses a single axis coarse and fine adjusting device which has been provided with an intermediate adjusting mechanism. While this device does provide an alternative adjustment between coarse and fine, it is complicated in construction requiring a high degree of precision in manufacture and assembly. Further, the intermediate adjustment provided for in the Shio patent is limited by the interaction of the coarse and fine assemblies. A further disadvantage of this mechanism is that it is mounted coaxially with the coarse and fine mechanism which, for some operators may be awkward to manipulate.
In U.S. Ser. No. 385,734 filed June 7, 1982 James A. Clark (now U.S. Pat. No. 4,482,221), the inventor of the instant device, disclosed a device which would provide an adjustment in addition to the normal coarse and fine adjustments. Although the device was mounted coaxially with the coarse and fine shafts, it included a mechanism which could easily be manipulated by the operator. However, this mechanism, while solving some problems, is restricted to the amount of adjustment that can be accomplished in that the mechanism allows for only very limited movement.
Therefore, it will be seen that the above described adjusting mechanisms suffer from a variety of problems, such as cost, complexity of construction which requires a highly skilled technician to assemble and poor replacement of parts.
As will be detailed hereinafter, the adjusting mechanism of the present invention presents a solution to the problems set forth above by providing an auxiliary mechanism which is easily manipulated to give an alternative choice to the normal coarse and fine adjustments. The adjusting mechanism is economical to manufacture, easy to assemble and accurate within very tight tolerances.